I am leaning transformations also. This is how I understand translation and reflection.
Translation is a slide, moving without flipping.
Reflection is a flip, moving with flipping.
So, to reflect over one line, one flip, the preimage and image are different.
To reflect over two parallel lines, it is two flips, the preimage and image are the same after two flips.
I know you understand it now. Just want to show my method, cuz I think it is easier to visualize.